Oil compositions containing alkyl mercaptan derivatives of copolymers of an alpha olefin or an alkyl vinyl ether and an unsaturated alpha, beta-dicarboxylic compound

ABSTRACT

Oil compositions comprising crude oils, fuel oils, mineral oils and synthetic oils having high pour points are provided with one or more enhanced characteristics such as improved pour point, viscosity or viscosity index by the addition of alkyl amine or alkyl mercaptan derivatives of a copolymer comprising an alpha olefin or an alkyl vinyl ether and maleic anhydride.

This is a division of application Ser. No. 265,614, filed oct. 31, 1988,now U.S. Pat. No. 4,900,331.

BACKGROUND OF THE INVENTION

1. Field Of The Invention

This invention relates to oil compositions comprising crude oils,mineral oils, fuel oils and synthetic oils having one or more improvedcharacteristics, such as pour point viscosity, viscosity index,flowability and the like.

Crude, refined and synthetic oils frequently require modification or theaddition of additives to improve one or more of their physicalcharacteristics, such as, pour point, viscosity, viscosity index, etc.In particular, one more more of the above-described properties isimparted to oil compositions by the addition thereto of copolymerscomprising an alkyl amine or alkyl mercaptan derivative of an alphaolefin or an alkyl vinyl ether and maleic anhydride. The copendingapplication of Hanh T. Le entitled "Alkyl Amine or Alkyl MercaptanDerivatives Of An Alpha Olefin Or Alkyl Vinyl Ether And An Alpha,Beta.Dicarboxylic Compound", Ser. No. 265,611, filed Oct. 31, 1988 ,describes in detail how to prepare these compounds.

Crude oils, depending upon the location of production may containsubstantial quantities of wax. This wax is subject to separation whenthe crude oil is cooled below the pour point index of the oil.Crystallized wax precipitates from crude oil at sufficiently lowtemperatures and the oil, as well, can completely solidify causingreduced flowability and or pumpability of the oil.

When crude oil is produced from a production well through strata havinglower temperatures than that of the oil-bearing bearing formations, thecrude oil may gel or transform into a dense or glutinous consistency,which can interfere with its transfer to the surface. The problem ofcrude oil and oil compositions solidifying, especially during extremeweather conditions is further emphasized during the storage of the oilin tanks which do not have insulation or heating facilities or intransporting the oil in unheated tankers or through a pipeline.

Thus, acceptable pour points and flow characteristics of an oilcomposition are highly desirable, particularly during production andupon storage, and transport of the oil composition; and especiallyduring a refining operation when the oil composition is a crude oil. Itshould be noted that the copolymers herein, when incorporated in an oilcomposition, substantially lower the pour point and concomitantlyenhance the flowability of the oil composition.

2. Description Of The Prior Art

Processes and catalysts for the production of polymers and copolymers oforganic compositions as oil additives are known and are currentlypracticed commercially.

For example, U.S. Pat. 3,677,725 relates to copolymers of (1) maleicanhydride and an alpha olefin or an alkylvinylether and (2) alkyl estersof carboxymethyl amides or carboxymethyl esters of maleic anhydride,alpha olefins or alkyl. vinylethers. These copolymers are described asuseful for imparting antistatic properties to distillate fuel oils andother volatile liquid compositions.

U.S. Pat. 3,694,176 discloses copolymers of ethylene and an alpha betaethylenically unsaturated dicarboxylic acid or its anhydride or mono ordiester. The copolymers are described as suitable for use as wax crystalmodifiers, pour point depressants and dewaxing aids for hydrocarbonoils.

U.S. 3,776,247 relates to a composition of matter having improved flowand friction, reducing properties which consists of a waxy crude oilcontaining a polymer selected from copolymers of anhydrides ofdicarboxylic acids and mono olefins or alkylvinylether copolymerizedwith the dialkylester of an unsaturated acid.

U.S. Pat. 3,879,177 discloses a process for inhibiting thecrystallization of wax from a waxy crude oil produced from asubterranean formation by adding to the waxy oil a copolymer of maleicanhydride and vinylmethyl ether esterified with an alcohol containing 18to 24 carbon atoms.

U.S. Pat. 4,240,916 relates to lubricating oil compositions havingenhanced pour point depressant properties. Copolymers of maleicanhydride and alpha olefins are described as suitable for use in the oilcompositions.

As can readily be determined from the above, there is an ongoing searchfor newer and more effective polymers and copolymers for use as pourpoint depressants in oil compositions. It should be noted, however, thatthe specific amine or mercaptan derivatives of the copolymers herein arenew.

SUMMARY OF THE INVENTION

This invention encompasses new compositions that are particularlysuitable for use as pour point depressants for oil compositions. Inparticular, the invention relates to oil compositions which comprise anamjor amount of an oil selected from a crude oil, fuel oil, mineral oilor a synthetic oil and a minor amount of an alkyl amine or alkylmercaptan derivative of an alpha olefin or alkyl vinyl ether and anunsaturated alpha, beta dicarboxylic compound having pour pointdepressant properties. said copolymer comprising the reaction product of(a) an alpha olefin or a mixture of alpha olefins or a monomeric alkylvinyl ether or a mixture of alpha olefins or alkyl vinyl ethers havingthe formula: ##STR1## wherein Z₁ and Z₂ are the same or different, H, 0R₁, R₁ or OR₁ and R₁ is an alkyl group having 1 to 30 carbon atoms, (b)maleic anhydride; and (c) an alkyl amine or alkyl sulfide or a mixtureof alkyl amines or alkyl sulfides having the formula:

    X(R.sub.2).sub.y

wherein X is N or S and R₂ is an alkyl group having from about 3 toabout 30 carbon atoms and y is either 1 or 2.

DETAILED DESCRIPTION OF THE INVENTION

The present invention resides in oil compositions and to alkyl amine oralkyl mercaptan derivatives of copolymers comprising an alpha olefin oralkylvinyl ether/maleic anhydride which are particularly suitable foruse in said oil compositions as pour point additives.

The alpha olefins of the present invention are derived commercially frompetroleum stocks or by the dehydration of alcohols and by the pyrolysisof paraffin waxes. Significant quantities of olefins are produced bythermal and catalytic cracking of various liquid petroleum fractionsusing conventional catalysts.

More recently linear olefins in general and alpha olefins in particularhave been produced by ethylene oligomerization processes based onZiegler Chemistry. In the ethylene. oligomerization process, theoligomerization of ethylene using a Ziegler catalyst, e.g.,triethylaluminum, takes place wherein ethylene adds to triethylaluminumby insertion between the aluminum atom and one of the alkyl groups untila selected average alkyl size is reached. The alkyl is converted to thecorresponding olefin by displacement with a lower olefin. e.g., usuallyethylene. The growth reaction is normally carried out at greater than100° C., at higher temperatures an increasing proportion of theunreacted ethylene displaces the alkyl group from the metal alkyl and at300° C., displacement is the predominant reaction. Suitable alphaolefins contain from about 2 to about 30 carbon atoms. especially fromabout 4 to about 28 carbon atoms, preferably from about 8 to about 24carbon atoms.

Desirable alpha olefins are preferably selected from the groupconsisting of ethylene, propene, butene, pentene, hexene, heptene,octene, nonene, decene, undecene, dodecene, tridecene, tetradecene,pentadecene, hexadecene, heptacene, octadecene, nonodecene, eicosene,heneicosene, docosene tricosene, tetra, cosene, pentacosene, hexacosene,heptacosene, octacosene, non, acosene and triacontene and mixturesthereof.

It is to be noted that the individual alpha olefins can be incorporatedinto the copolymers herein. However mixtures of the alpha olefins arehighly desirable in the production of said copolymers. Mixtures of alphaolefins preferably are those alpha olefins which contain from about 4 toabout 28 carbon atoms.

Similarly, the alkyl vinyl ethers suitable for use herein have theformula: ##STR2## wherein Z₁ and Z₂ are the same or different, H, R₁, R₁or OR₁ and R₁ is an alkyl group having 1 to 30 carbon atoms.

These compounds preferably are classified as the alkyl vinyl ethers. Thealkyl moiety of the compound generally contains from about 1 to about 30carbon atoms, preferably from about 4 to about 28 carbon atoms, mostpreferably from about 4 to about 24 carbon atoms.

One method of producing the alkyl vinyl ethers herein involves theoxidation of ethylene and an alkyl alcohol in contact with a palladiumchloride cuprous chloride hydrogen chloride catalyst using conventionaltechniques and methods. Another typical method of producing the alkylvinyl ethers herein is by the reaction of an alcohol with vinyl acetatein contact with a palladium tungsten catalyst.

The alkyl vinyl ethers preferably are members selected from the groupconsisting of methylvinyl ether, ethylvinyl ether, propylvinyl ether,butylvinyl ether, pentylvinyl ether, hexylvinyl ether, heptylvinylether, octylvinyl ether, nonylvinyl ether, decylvinyl ether,undecylvinyl ether, dodecylvinyl ether, tri, decylvinyl ether,tetradecylvinyl ether, pentadecylvinyl ether, hexadecylvinyl ether,heptadecylvinyl ether, octadecylvinyl ether, nonadecylvinyl ether,eicosylvinyl ether, heneicosylvinyl ether, docosylvinyl ether,tricosylvinyl ether, tetracosylvinyl ether, pentacosylvinyl ether,hexacosylvinyl ether, heptacosylvinyl ether, octacosylvinyl ether,nonacosylvinyl ether and tri acontylvinyl ether and mixtures thereof.

The second monomer of the copolymers herein comprises maleic anhydridewhich derives its common name from malic acid, a related compound. Onetypical method of preparing maleic anhydride has been the catalyticoxidation of benzene using. for example, a vanadium oxide catalyst.

More recently, maleic anhydride has been prepared via the vapor-phaseoxidation of hydrocarbons, such as benzene, n-butane and n-butene, usinga conventional oxidation catalyst. The hydrocarbon-oxidation reactioninvolves oxidation of a relatively low concentration of hydrocarbon inair to form maleic anhydride, carbon oxides, water and smaller amountsof partially oxidized by-products.

The third component of the copolymers herein include an alkyl amine oran alkyl mercaptan. Generally, the alkyl amine or alkyl mercaptan hereinwill react with the maleic anhydride moiety of the copolymers hereinafter the copolymers have been produced The alkyl amines or alkylmercaptans have the formula:

    X(R.sub.2).sub.y

wherein X is N or S and R₂ is an alkyl group having from about 3 toabout 30 carbon atoms and y is either 1 or 2.

There are several known methods for the preparation of alkyl amines, butthe most common method is the conversion of a fatty acid or a mixture offatty acids to a nitrile by treating with ammonia, followed by catalytichydrogenation of the nitrile to either a primary, secondary or tertiaryamine by suitable adjustment of the reaction conditions. Particularly,ammonia and fatty acid in a batch process are allowed to react at about200° C. under a pressure of 50 to 100 psig for about 10 to 12 hours Therate of ammonia addition is adjusted so that a slight pressure ismaintained in the reactor. Ammonia and water are continuously vented tofacilitate completion of the reaction. Boric acid. aluminum oxide ortitanium and zinc alkoxides are typical catalysts used in the reaction.

The alkyl mercaptans herein are generally produced by reacting hydrogensulfide with olefins typically using a phosphite catalyst or an acidiccatalyst in a free radical initiation reaction. Another method ofproducing alkyl mercaptans involves reacting hydrogen sulfide with analcohol under acid catalyzed conditions, usually with conventional solidacidic catalysts.

The alkyl amines and alkyl mercaptans generally have from about 3 toabout 30 carbon atoms, especially from about 4 to about 24 carbon atoms.preferably from about 4 to about 20 carbon atoms. The alkyl moiety ofthe amines and mercaptans typically are members selected from the groupconsisting of propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl,undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl,tricosyl, tetracosyl, pentacosyl, hexacosyl, heptacosyl, octacosyl, non,acosyl and triacontyl moieties and mixtures thereof.

The copolymers useful in the practice of this invention can be preparedin a conventional manner by bulk, solution or dispersant polymerizationmethods using known catalysts. Thus the copolymers utilized by thisinvention can be prepared from the corresponding monomers with a diluentsuch as water in a heteroge neous system, usually referred to asemulsion or suspension polymerization, or with a solvent such astoluene, xylene, benzene, ethylene dichloride, methyl isobutyl ketone,4-methyl 2-pentanone or in a homogeneous system, normally referred to assolution polymerization. Solution polymerization for example in toluene,xylene, methyl isobutyl ketone, 4-methyl 2-pentanone or a solvent havingsimilar chain transfer activity is the preferred method used in formingthe copolymers disclosed herein, because this method and solvent producepreferred copolymers characterized by a molecular weight in the range offrom about 5,000 to about 100,000. When the copolymer is dissolved in asolvent, the solvent normally will comprise from about 40 to about 90weight percent based on the weight of the copolymer or individualmonomers and amine or mercaptan compounds which combine to produce thecopolymer.

Polymerization of the monomers used herein readily takes place under theinfluence of heat, light and/or catalysts. Suitable catalysts includefree radical catalysts such as t-butyl perbenzoate, azo bis isobutylnitrile and peroxide type free radical catalysts such as benzoylperoxide, lauryl peroxide, or t-butylhydroperoxide. The preferred freeradical catalysts are azo bis isobutyl nitrile and t-butyl-perbenzoate.The catalysts, when used, are employed in concentrations ranging from afew hundreds percent to two percent by weight of the monomers. Thepreferred concentration is from about 0.2 to about 1.0 percent by weightof the monomers.

Copolymerization of the monomers used herein takes place over a fairlybroad temperature range depending upon the particular monomers andcatalyst utilized in the reaction. For example, polymerization can takeplace at temperatures from about 70° C. to about 200° C. Thus, apreferred temperature range is form about 70° C. to 150° C. anespecially preferred temperature range is from about 70° C. to about130° C. The polymerization reaction is preferably carried out in aninert atmosphere, for example, nitrogen or argon to favor the formationof copolymers that have the desired molecular weights and highviscosities. The reactions are preferably conducted at ambient pressure,however it is to be noted that higher pressures can be used for example,pressures of from about ambient pressure to about 25 psig can beemployed in the reaction.

Preferably, the polymerization reaction is carried out to substantialcompletion so that the finished product is essentially comprised of theratio of monomers introduced into the reaction vessel. Normally, areaction time of from 1 to about 72 hours, preferably from 1 to about 50hours, especially from 1 to about 10 hours, is sufficient to completethe polymerization process.

Specific examples of the copolymers which can be used according to theinvention are the 0.01:0.01 to 1.0:1.0, especially the 0.01:0.01 to 0.8:0.8 molar ratio of (a) alpha olefin or alkyl vinyl ether and (b) maleicanhydride.

In a preferred mode, the (1) alpha olefin or alkyl vinyl ether and (2)unsaturated alpha, beta dicarboxylic compound are reacted under thedisclosed reaction conditions to form the copolymers herein. Then, thecompleted copolymers are contacted with an alkyl amine or alkylmercaptan under reaction conditions to form the alkyl amine or alkylmercaptan derivatives of the copolymers . The reaction conditionsutilized for producing the copolymers herein are suitable for use in thealkyl amine and alkyl mercaptan reactions, except that the free radicalpolymerization catalyst is not used in the reaction. While it is not tobe construed as being bound by theory, it is believed that the alkylamine or alkyl mercaptan attaches to the maleic anhydride moiety of thecopolymer to form alkyl amine or alkyl mercaptan derivatives of thecopolymer. Thus, the copolymer and alkyl amine or alkyl mercaptan arecontacted at a temperature of from about 70° C. to about 200° C.,preferably from about 70° C. to about 150° C. at a pressure of fromabout ambient pressure to about 25 psig, for about 1 to about 72 hours,especially from about 1 to about 50 hours.

Preferably, it is desirable to add an excess of alkyl amine or alkylmercaptan to the reaction medium, so that all of the copolymer activesites undergo a reaction. Thus, the copolymer and alkyl amine or alkylmercaptan are reacted at from about 0.01 to 0.01 to about 1.0 to 2.0molar ratio. respectively. The alkyl amine or alkyl mercaptanderivatives of the copolymers herein have an average molecular weight ofgreater than about 1,000, especially a molecular weight range of fromabout 1.000 to about 100,000, especially from about 1.000 to about70.000, preferably from about 5,000 to about 50.000.

The copolymers described herein can be incorporated in a wide variety ofoil compositions, for example, crude oil. distillate fuel oils, mineraloils, and synthetic oils.

Crude oils, of course, are widely distributed around the world in theearth's crust as gases, liquids and solids. Crude oils are found asnatural gas; a variety of liquids that are usually classified as normalor heavy crude oils, sweet or sour crude oils, and semisolid and solidsubstances, such as asphalt, tar, pitch, gilsonite and many similarsubstances. The crude oils suitable for use herein, however, are thoseliquid crude oils that can be produced through a well bore by currentprimary, secondary or tertiary (enhanced recovery) techniques.

The distillate fuel oils herein may be of virgin or cracked petroleumstock, or mixtures thereof, boiling in the range of about 300° F.(148.9° C.) to about 705° F. (398.9° C.) and preferably in the range ofabout 350° F. (176.7° C.) to about 650o (343 3° C.) The fuel oil maycontain cracked components, such as for example, those derived fromcrude oils or cycle oil cuts boiling above gasoline, usually in therange of about 450° F. (232.2° C.) to about 750° F. (398.9° C.) and maybe derived by catalytic or thermal cracking. Oils of high or low sulfurcontent such as diesel oils may be used.

Preferred distillate fuel oils which are improved in accordance with theinvention have an initial boiling point within the range of about 350°F. (176.7° C.) to about 475° F. (246.l° C.) and an end boiling point inthe range of about 500° F. (260° C.) to about 650° F. (343.3° C.), anAPI gravity of at least 30 and a flash point (P.M) not lower than about110° F. (43.3° C.).

Suitable mineral oils include those oils that have been derived fromparaffinic, napthenic or mixed base crude petroleum oils. These oils mayhave been subjected to solvent or sulfuric acid treatment, aluminumchloride treatment, hydrogenation and or other refining treatments.

Synthetic oils as defined herein are those oils derived from a productof chemical synthesis or man made oils, as well as, shale oil, tar sandoil and oil derived from solid carbonaceous products, for example coal.

Shale oil consists of a marstone type sedimentary inorganic materialthat contains complex organic polymers which are high molecular weightsolids. Organic kerogen which is an integral component of shale oil, isa three dimensional polymer, is insoluble in conventional organicsolvents and is associated with small amounts of a benzene solublematerial, e.g., bitumen.

The composition of shale oil depends on the shale from which it wasobtained as well as the retorting method by which it was produced.Retorting or pyrolysis is the thermal decomposition of oil shale whichyields liquid, gaseous and solid products. The amounts of oil, gas andcoke which are ultimately formed, depend on the temperature time historyof the liberated oil and on the heating rate of the oil shale.

As compared with petroleum crude, shale oil contains large quantities ofolefinic hydrocarbons which cause gumming and an increased hydrogenrequirement for upgrading. High pour points are observed and smallquantities of arsenic and iron are present. Generally, crude shale oilcan be prerefined to produce a synthetic crude that is compatible withtypical refineries and refinery processes.

Tar sands, also known as oil sands and bituminous sands, are sanddeposits impregnated with dense, viscous petroleum. Tar sands arelocated throughout the world, often in the same geo. graphical areas asconventional petroleum. The bitumen can be separated from tar sands byseveral different methods to produce a synthetic crude oil. For example,the hot water separation process was an early method for recoveringbitumen and for producing a synthetic crude oil. Other methods forproducing a synthetic crude oil include in situ methods such as firefloods, steam drive and stimulation, and electric heating processes.More recent methods for producing synthetic crude oils from tar sandsinclude mining the tar sands and direct coking, hot water, cold. waterand solvent processes.

Synthetic liquid fuel and oils derived from solid carbonaceous productsare conveniently prepared by blending finely ground carbonaceousmaterials with a solvent to form a slurry. The slurry is then introducedinto a reaction vessel containing a conventional hydrogenation catalystand is reacted under normal hydrogenating pressures and temperatures.After hydrogenation, solids that are present can conveniently be removedfrom the product stream. The product is next stripped of solvent. Thebalance of the produce stream may be distilled to obtain products ofvarious boiling ranges, for example, hydrocarbons boiling in thegasoline range and hydrocarbons boiling in the lubrication oil range.Some of the products are useful as fuels and oils, the remainder can befurther treated by a conventional petroleum process including cracking,hydrocracking, and the like Synthetic liquid fuel and oils produced fromsolid carbonaceous products such as coal are primarily aromatic andgenerally have a boiling range of about 300° F. (149° C.) to about 1400°F. (760° C.), a density of about 0.1 to about 1.1 and a carbon tohydrogen molecular ratio in the range of about 1.3:1 to about 0.66:1. Atypical example is a solvent oil obtained from a subbituminous coal,such as Wyoming, Mont. coal; comprising a middle oil having a boilingrange of from about 375° F. (190.5° C.) to about 675° F. (375° C.)

The herein described copolymers can be incorporated in the oilcomposition in any convenient manner. Thus, the copolymers can be addeddirectly to the oil by dissolving the desired copolymer in the oilcomposition at the desired level of concentration. Normally thecopolymer is added to the oil at from about 0.01 to about 10 weightpercent, preferably from about 0.1 to about 5 weight percent by weightof the oil composition. Alternatively, the copolymers herein may beblended with suitable solvents to form concentrates that can be readilydissolved in the appropriate oil composition at the desiredconcentration. If a concentrate is employed, it ordinarily will containat least 10 to about 65 weight percent of the copolymer and preferablyabout 25 to about 65 weight percent of the copolymer. The solvent insuch a concentrate normally is present in amounts of about 35 to about75 percent by weight of the concentrate.

Solvents suitable for use in forming the concentrate herein include,petroleum based compounds, for example, naptha, kerosene, benzene,xylene, toluene, hexane, light mineral oil and mixtures thereof. Theparticular solvent selected should, of course, be selected so as not toadversely affect the other desired properties of the ultimate oilcomposition.

The following examples serve to demonstrate the best mode of how topractice the invention herein and should not be construed as alimitation thereof.

EXAMPLE I

An alkyl amine derivative of a copolymer of a mixture of C₂₄ to C₂₈alpha olefins (sold commercially by Chevron Corporation, San Francisco,Ca.) and maleic anhydride was prepared by adding 50 grams (0.142 mole)of C₂₄ to C₂₈ alpha olefin and 0.3 ml (0.0079) of t-butyl perbenzoate toa 1.liter, 4.neck Pyrex glass resin kettle with detachable top and 2screw caps (manufactured by ACE Glass Inc., Vineland, N.J.) equippedwith a mechanical stirrer, a heating mantle containing a thermal couple(manufactured by the Thermal Electric Co., Saddle Brook, N. J.), athermometer, a 250 ml addition funnel and a water cooled refluxcondenser. The top of the addition funnel was equipped with a rubberseptum and the top of the reflux condenser was equipped with a rubberstopper containing a clear plastic vacuum tube. The plastic tube fromthe rubber stopper connected to a firestone valve (manufactured by theAldrich Co., Milwaukee, Wisconsin) containing a lead to vacuum and alead to a gas source. Vacuum was supplied to the system by a PrecisionVacuum Pump. Model Number DD195, manufactured by the GCA Corporation.Precision Scientific Group, Chicago. Ill. The system was vacuumed at 5mm of Hg to remove air and flushed with nitrogen gas until the systemequalized at atmospheric pressure in the resin kettle. Alternatively, amagnetic stirring bar, including apparatus can be used to replace theglass mechanical stirrer.

To the addition funnel was added 17.2 grams of maleic anhydridedissolved in 100 ml of toluene and 8 ml of methyl isobutyl ketone. Thesolution in the resin kettle was heated to 120° C., the maleic anhydridesolution in the addition funnel was slowly added over a period of 4hours and the reaction mixture was heated for another 2 hours.

The copolymer thus produced, 30 grams (0.06 mole), was added to a 500 mlround bottom, pyrex glass flask equipped with heating mantle,thermometer, water cooled condenser, Deanstark water trap and vacuum andnitrogen gas inlet at the top of the water cooled condenser.

Next, to the Pyrex flask was added 22 grams (0.081 mole) of C₁₈ amineand 100 ml of xylene. The reaction mixture was refluxed overnight (20hours) under nitrogen atmosphere. The solvent was removed by evaporationand the reaction product formulated into a 10 weight percent toluenesolution and tested for pour point activity.

EXAMPLE II

The procedure of Example I was followed to produce an octadecylmercaptan derivative of a C₂₄ to C₂₈ olefin/maleic anhydride copolymerwith the following exceptions:

to the Pyrex flask was added 15 grams (0.033 mole) of C₂₄ to C₂₈olefin/maleic anhydride copolymer and 12 grams (0.041 mole) of octadecylsulfide mixed with 100 ml of xylene. The reaction mixture was refluxedovernight (19 hours) under nitrogen atmosphere. Next, the solvent wasstripped from the reaction product and the product was heated at 195° C.and 1 mm Hg for one hour. The reaction product (26 grams with a 96percent yield) was added to toluene (10 weight percent solution) andtested for pour point activity.

EXAMPLE III

An octadecyl amine derivative of 1.octadecene/maleic anhydride copolymerwas produced by adding 30 grams (0.085 mole) of 1.octadecene/maleicanhydride copolymer, purchased from the Polyscience Company, and 22grams (0.081 mole) of octadecyl amine mixed with 100 ml of xylene to a500 ml round bottom, Pyrex-glass flask equipped with heating mantle,thermometer, water cooled condenser, Deanstark water trap and vacuum andnitrogen gas inlet at the top of the water cooled condenser. Thereaction mixture was refluxed overnight (20 hours), and the waterproduced in the reaction discarded. The solvent was then stripped fromthe reaction product (62 grams) and a 10 weight percent in toluenesolution was formulated.

EXAMPLE IV

An octadecyl amine derivative of octadecylvinyl ether/. maleic anhydridecopolymer was produced in accordance with the procedure of Example IIIwith the following exceptions:

To the Pyrex flask was added 30 grams (0.03 mole) of octadecylvinylether/maleic anhydride copolymer. The copolymer was purchased from theAldrich Chemical Company, Milwaukee, Wis. which sells the copolymercommercially. Then, 12 grams (0.045 mole) of octadecylamine and 200 mlof xylene were added to the Pyrex flask. The reaction mixture wasrefluxed overnight (20 hours) under nitrogen atmosphere and the waterwhich collected in the Deanstark trap was discarded. The solvent wasstripped from the reaction product (20 grams with an 87 percent yield)and the reaction product was added to toluene (10 weight percentsolution).

EXAMPLE V

An octadecyl mercaptan derivative of octadecylvinyl ether/maleicanhydride copolymer was produced using the procedure of Example IV withthe following exceptions:

Octadecyl sulfide, 12 grams (0.041 mole), was substituted for theoctadecyl amine. The reaction mixture was refluxed overnight (18 hours)under nitrogen atmosphere and the water collected in the Deanstark trapwas discarded. The solvent was stripped from the reaction product (20grams with an 83 percent yield) and the reaction product was formulatedinto a 10 weight percent solution in toluene.

EXAMPLES VI TO XI

The pour point enhancing properties of the polymers produced in ExamplesI through V were tested in accordance with the procedure set forth inASTM-D97. The pour point properties of the polymers of Examples Ithrough V were compared with Shellswim 5X® Shellswim 11T®, two wellknown pour point depressa marketed commercially by the Shell OilCompany, Houston, Tex. All of the additives were added to the oilcompositions at concentrations of 1,000 ppm active and 46.11° C.preheat. The results are tabulated in Table 1 below.

                                      TABLE 1                                     __________________________________________________________________________    POUR POINT (°C.)                                                                     Polymer                                                                            Polymer                                                                             Polymer                                                                             Polymer                                                                             Polymer                                                                             Shellswim                                                                           Shellswim                    Ex.                                                                              Crude Oils                                                                           Blank                                                                             Of Ex. I.sup.1                                                                     Of Ex. II.sup.2                                                                     Of Ex. III.sup.3                                                                    Of Ex. IV.sup.4                                                                     Of Ex. V.sup.5                                                                      5X ®.sup.6                                                                      11T ®.sup.7              __________________________________________________________________________    VI Kotter 27  27   --    --    2     29    10     7                           VII                                                                              Delhi 87                                                                             24  18   21    16    16    13    21    21                           VIII                                                                             New Zealand                                                                          32  10   27     2    21    29    21    21                           IX Bombay 29   7   27    32    --    35    10    13                           X  Salam  21  16   --    --    2     -29   16    10                           XI Agiba  18   2   --    --    -7    -12   --    --                           __________________________________________________________________________     .sup.1 polymer of Ex. I  C.sub.18 amine derivative of C.sub.24 -C.sub.28      olefin/maleic anhydride copolymer                                             .sup.2 polymer of Ex. II  C.sub.18 mercaptan derivative of C.sub.24           -C.sub.28    olefin/maleic anhydride copolymer                                .sup.3 polymer of Ex. III  C.sub.18 amine derivative of C.sub.18              olefin/maleic anhydride copolymer                                             .sup.4 polymer of Ex. IV  C.sub.18 amine derivative of octadecyl              ether/maleic anhydride copolymer                                              .sup.5 polymer of Ex. V  C.sub.18 mercaptan derivative of octadecyl           ether/maleic anhydride copolymer                                              .sup.6 Shellswim 5X ® A C.sub.18 -C.sub.22  alkylacrylate ester           homopolymer, sold commercially by the Shell Oil Company, Houston, Texas       .sup.7 Shellswim 11T ® A C.sub.18 -C.sub.22 alkylacrylate/4 vinyl         pyridine copolymer sold commercially by the Shell Oil Company, Houston,       Texas                                                                    

As can readily be determined from the above test results, the copolymersproduced according to the procedure set forth herein gave superior orcomparable pour point results when compared to commercial pour pointadditives for crude oils.

Obviously, many modifications and variations of the invention, as hereinabove set forth, can be made without departing from the spirit and scopethereof and therefore only such limitations should be imposed as areindicated in the appended claims.

I claim:
 1. An oil composition which comprises a major amount of an oilselected from a mineral oil or synthetic oil and a manor amount of analkyl mercaptan derivative of an alpha olefin or alkyl vinyl ether andan unsaturated alpha, beta-dicarboxylic compound copolymer having pourpoint depressant properties, said copolymer comprising the reactionproduct of (a) an alpha a olefin having from about 2 to about b 30carbon atoms or mixtures of alpha olefins having from about 2 to about30 carbonates or an alkyl vinyl ether or mixture of alkyl vinyl ethershaving the formula: ##STR3## wherein Z₁ and Z₂ are the same ordifferent, H, R₁ or OR₁ and R₁ is an alkyl group having 1 to 30 carbonatoms, (b) maleic anhydride; and (c) an alkyl sulfide having theformula:

    X(R.sub.2).sub.y

wherein X is S and R₂ is an alkyl group having from about 3 to about 30carbon atoms and y is either 1 or
 2. 2. The oil composition of claim 1wherein components (a), (b) and (c) are reacted in a molar ratio of fromabout 0.01: 0.01: 0.01 to about 1.0: 1.0: 2.0, said copolymer having amolecular weight of at least about 1,000.
 3. The oil composition ofclaim 1 having a molecular weight of from about 1,000 to about 100,000.4. The oil composition of claim 1 wherein R₁ of component (a) is alkylhaving from about 4 to about 28 carbon atoms.
 5. The oil composition ofclaim 1 wherein the alpha olefin of component (aa) ia a member selectedfrom the group consisting of ethylene, propene, butene, epnetene,hexene, heptene, octene, nonene, decene, undeecene, dodecene, tridecene,tetradecene, pentadecene, hexadecene, heptacene, octadecene, nonodecene,eicosene, heneicosene, docosene, tricosene, tetracosene, pentacosene,hexacosene, heptacosene, octacosene, nonacosene and triacontene andmixtures thereof.
 6. The oil composition of claim 1 wherein the alkylvinyl ether of component (a) ia a member selected from the groupconsisting of methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether,butyl vinyl ether, pentyl vinyl ether, hexyl vinyl either, heptyl vinylether, octyl vinyl ether, nonyl vinyl ether, decyl vinyl ether, undecylvinyl ether, dodecyl vinyl ether, tridecyl vinyl ether, tetracecylvineykl ether, pentadecyl vinyl ether, hexadecyl vinyl ether,heptacdecyl vinyl ether, octadecyl vinyl ether, nonadecyl vinyl ether,eicosyl vinyl ether, heneicosyl vinyl ether, docosyl vinyl ether,tricosy vinyl either, tetracosyl vinyl ether, pentacosyl vinyl ether,hexacosyl vinyl ether, heptacosyl vinyl ether, octacosyl vinyl ether,nonacosyl viney ether and triacosyl vinyl ether and mixtures thereof. 7.The oil composition of claim 1 wherein the alkyl sulfide of component(c) is a member selected from the group consisting of propyl sulfide,butyl sulfide, pentyl sulfide, hexyl sulfide, heptyl sulfide, octylsulfide, nonyl sulfide, decyl sulfide, undecyl sulfide, dodecyl sulfide,tridecyl sulfide, tetracdecyl sulfide, pentacecyl sulfide, hexadecylsulfide, heptadecyl sulfide, octadecyl sulfide, nonadecyl sulfide,eicosyl sulfide, heneicosyl sulfide, docosyl sulfide, tricosyl sulfide,tetracosyl sulfide, pentacosyl sulfide, hexacosyl sulfide heptacodylsulfide, octacosyl sulfide, nonacosyl sulfide and triacosyl sulfide andmixtures thereof.
 8. The oil composition of claim 1 wherein thecopolymer comprises from about 0.01 weight percent to about 10 weightpercent of said coil composition.
 9. The oil composition of claim 1wherein the copolymer comprises from about 0.1 weight percent to about 5weight percent of said oil composition.
 10. An oil composition whichcomprises a major amount of an oil selected from a mineral oil orsynthetic oil and a minor amount of a copolymer having pour pointdepressant properties which is obtained by free radical polymerizationof a monomeric mixture comprising from about 0.01 to about 1.0 molarpercent of (a) an alpha olefin or an alkyl vinyl ether having theformula: ##STR4## wherein Z₁ and Z₂ are the same or different, H, R₁ orOR₁ and R₁ is an alkyl group having 1 to about 30 carbon atoms, (b) fromabout 0.01 to about 1.0 molar percent of maleic anhydride to obtain acopolymer; and (c) by the reaction of from about 0.02 to about 2.0 molarpercent of an alkyl sulfide with from about 0.01 to about 1.0 molarpercent of the copolymer, said alkyl sulfide having the formula:

    X(R.sub.2).sub.y

wherein X is S and R₂ is an alkyl group having from about 3 to about 30carbon atoms and y is either 1 or
 2. 11. The oil composition of claim 10wherein R₁ of component (a) is an alkyl group having from about 4 toabout 28 carbon atoms.
 12. The oil composition of claim 10 having amolecular weight of from about 1,000 to about 70,000.
 13. The oilcomposition of claim 10 wherein the alpha olefin is a member selectedfrom the group consisting of ethylene, propene, butene, pentene, hexane,heptene, octene, nonene, decene, undecene, dodecene, tridecene,tetradecene, pentadecene, hexadecene, heptacene, octadecene, nonodecene,eicosene, heneicosene, doceosene, tricosene, tetracosene, pentacosene,hexacosene, heptacosene, octacosene, nonacosene and triacontene andmixtures thereof.
 14. The oil composition of claim 10 wherein the alkylvinyl ether component (a) is a member selected from the group consistingof methyl vinyl either, ethyl vinyl either, porpoly vinyl either, butylvinyl ether, pentyl vinyl either, hexyl vinyl either, ppheptyl vinylether, octyl vinyl ether, nonyl vinyl either, decyl vinyl ether, undecylvinyl ether, dodecyl vinyl ether, tridecyl vinyl either, tetracecylvinyl ether, pentacecyl vinyl ether, hexadecyl vinyl ether, heptacecylvinyl ether, octadecyl vinyl ether, nonadecyl vinyl ether, eiciosylvinyl ether, heneicosyl vinyl ether, oocosyl vinyl eitherk tricosylvinyl etherk tetracosyl vinyl either, pentacosyl vinyl either, hexacosylvinyl either, heptacosyl vinyl ethetr, octacosyl vinyl ther, nonacosylvinyl ether and triacosyl vinyl either and mixtures thereof.
 15. The oilcomposition of claim 10 wherein the alkyl sulfide of component (c) is amember selected from the group consisting of propul sulfide,butylsulfide, pentyl sulfide, hexyl sufide, heptyl sulfide, octylsulfide, nonyl sulfide, decyl sulfide, undecyl sulfide, dodecyl sulfide,tridecyl sulfide, tetrdecyl sulfide, pentaceecyl sulfide, hexadecylsulfide, heptadecyl sulfide, octadecyl sulfide, nonadecyl sulfide,eicosyl sulfide, heneicosyl sulfide, docosyl sulfide, tricosyl sulfide,tetracosyl sulfide, pentacosyl sulfide, hexacosyl sulfide, heptacosylsulfide, octacosyl sulfide, nonacosyl sulfide and triacosyl sulfide andmixturesx thereof.
 16. The oil composition of claim 10 wherein thecopolymer comprises from about 0.01 weight percent to about 10 weightpercent of said oil composition.
 17. The oil composition of claim 10wherein the copolymer comprises from about 0.1 weight percent to about 5weight percent of said oil composition.